sleep lecture Flashcards
What is sleep?
Reversible
Behavioral state of
perceptual disengagement from
Unresponsiveness to the environment
Some features of normal sleep
- Postural recumbency
- quiescence
- closed eyes
What defines sleep stages:
- EEG
- EOG - electrooculogram
- EMG of chin muscle tone (axial muscle tone)
(4. Polysomnogram - PSG measures respiratory effort, oxygenation, ECG, surface EMG - limbs)
What are some key neurotransmitters of the waking state?
- Histamine (tuberomamillary nucleus)
- NE (locus ceruleus)
- Serotonin (Raphe nuclei)
- Ach (basal forebrain)
Features of the waking state
- EEG: Low voltage, high frequency, dominant alpha rhythm
- EOG: rapid,blinking
- EMG: muscle tone is high
Features of stage N1 - very light quality sleep or sleep disruption
- EEG: <50% alpha, mostly theta activity
- EOG: slow roving eye movement
- EMG: Muscle tone is high
Features of stage N2
- EEG: Vertex K complexes, high voltage negative and positive discharges with spindles (~0.5s)
- EOG: Still
- EMG: Muscle tone is high
Features of stage N3
- EEG: Slow wave activity, high voltage, low frequency
- EOG: Still
- EMG: Muscle tone is LOW
- Homeostatic sleep
- reduced BP,HR, Cardiac output, RR
- GH release
Features of REM sleep
- EEG: Mixed frequency, low voltage, saw tooth waves
- EOG: rapid eye movements
- Muscle tone VERY low (paralyzed)
- Cholinergic brain state
- Irregular respiration, arrthymias, heart rate variation, classical dreaming state
What is the tonic phase of REM sleep?
- Impaired thermoregulation
- hypotension
- bradycardia
- increased CBF
- Increased ICP
- increased RR
- Erection
- ATONIA
What is the phasic phase of REM sleep?
- Vasoconstriction
- Increased BP
- Tachycardia
- Increases in CBF
- Increases in RR
How is REM sleep generated?
- Pons is a critical structure
- REM-on and REM-off cells
- Interaction between NE, 5HT, LDTN/PPN
- Sublateral dorsal and preceruleus (GABA) interact with vIPAG and LPT REM-off cells (REM flip-flop; Saper Nature)
What does a hypnogram for rem sleep look like?
- 90 minute cycles
- Increasing REM time, decreases SWS
- Stage N1 ~5%
- Stage N2 ~50%
- Stage N3 ~20%
- REM ~25%
What are some features of control of sleep?
- Process S- sleepiness Process C - circadian
- orexin/hypocretin project to POST hypothal
- sleep onset correlates with activity of VLPO (ant hypoth) - ANTERIOR HYPOTH
- Hypnogenic peptides IL-1 - TNF - sick want to sleep
- Adenosine increases with time spent awake - improve alertness with caffeine adenosine antagonist
- Dim light suppresses melatonin (rises in the evening)
- Increase in glymphatic space
How many hours of sleep do new borns get? How much REM sleep?
18 hours, 50% REM
How many hours of sleep do adolescents get?
10 hours
How many hours of sleep do adults get?
7-9 hours but get insufficient amounts
How many hours do elderly get?
reduced sleep due to sleep disorders
What changes in delta sleep ?
Decreases with age, confounded by definitional problems
What is sleep onset latency?
Time from lights out to sleep (~10min)
What is REM latency?
Time from sleep onset to REM sleep (~90min)
What is sleep efficiency?
Time asleep/Time in bed (~90%)
What drugs are associated with increases in sleep?
- antihistamines
How are benzodiazepines associated with sleep?
- benzodiazepines reduce slow wave sleep
how are antidepressants associated with sleep?
- Antidepressants (MAO-i, SSRI, TCA) reduce REM, prolong REM latency
How are SSRIs associated with sleep?
alter muscle tone
produce roving eye movements in light sleep
How does alcohol alter sleep?
Hastens sleep onset but associates with increased arousal
What are key markers of circadian rhythms?
- Temperature
- REM timing
- cortisol - rise in the morning whether you sleep or not - sleep doesn’t influence this
How is the nature of circadian vs sleep effects revealed?
By forced descychronization
How is circadian rhythm controlled?
transplantation of suprachiasmatic nuclei
What are the SCN afferents for circadian control?
- retinohypothalamic
- lateral geniculate
- Raphe
What are the SCN Efferents for circadian control?
- Paraventricular nuclei
- hypothalamus
- thalamus
- dorsomedial hypothal
What are some clock genes
- Clock
- Bmal
- Per
- Cry
There is a strong influence of the SCN on slave organs which are those?
Kidney
Liver
Sleep apnea more common in..
early morning - worse in REM sleep
What is apnea
cessation of breathing for 10 seconds
Hypopnea
Reduced breathin/ariflow 10 seconds
Obstructive apnea
Airway closed and paradoxical breathing
Central apnea
No movement of ribcage/abdomen
brainstem problem
broken neck kink in medulla
common in myotonic dystrophy
how do you distinguish rsetless leg from a neuropathy
- circadian component
- movement component
What is period limb movement/
Cyclical - predictable
Manifests as restless leg (the sensation)
90% of RLS have PLMD
50% of PLMD have RLS
CAUSES of RLS/PLMD
- central spasticit - PNS - MS - neurpathy
- alcohol use
- pregnancy (iron deficiency - fetus taking iron away)
Treatment of RLS
- supplement with iron or folate
- Dopaminergic AGONIST
- Sinemet (augments) - PD disease - only works for 6 months
- Clonazepam (tachyphylaxis)
- Opoids - exception circumstance
what is the classis tetrad for narcolepsy
- excessive day time sleepiness
- cataplexy - telling a joke then collapsing
- hypnagogic hallcuinations
- sleep paralysis
go into REM earlu - before 90min
Autoimmune BASIS - HLA
H1N1 - can be associated with this
How do you improve alertness in narcoplepsy?
Use amphetamines/alerting agents
- Anticataleptics - Anticholinergics, TCAs, SSRIs, Methylphenidate
How do Orexin and hypocretin work?
Knock out induces narcolepsy
Sleep walking would occur
First third of the night
REM Sleep behavior disorder occurs
LAST THIRD of the night
